# Subclass of Archive that can be understood by a C program (see launch.c).
# Copyright (C) 2005, Giovanni Bajo
# Based on previous work under copyright (c) 1999, 2002 McMillan Enterprises, Inc.
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License
# as published by the Free Software Foundation; either version 2
# of the License, or (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA
import archive
import struct
try:
  import zlib
except ImportError:
  zlib = archive.DummyZlib()
import sys
if sys.version[0] == '1':
    import strop
    find = strop.find
    split = strop.split
else:
    def find(s, sub):
        return s.find(sub)
    def split(s, delim, count):
        return s.split(delim, count)

class CTOC:
  """A class encapsulating the table of contents of a CArchive.

     When written to disk, it is easily read from C."""
  ENTRYSTRUCT = '!iiiibc' #(structlen, dpos, dlen, ulen, flag, typcd) followed by name
  def __init__(self):
    self.data = []

  def frombinary(self, s):
    """Decode the binary string into an in memory list.

        S is a binary string."""
    entrylen = struct.calcsize(self.ENTRYSTRUCT)
    p = 0
    while p<len(s):
      (slen, dpos, dlen, ulen, flag, typcd) = struct.unpack(self.ENTRYSTRUCT,
                                                  s[p:p+entrylen])
      nmlen = slen - entrylen
      p = p + entrylen
      (nm,) = struct.unpack(`nmlen`+'s', s[p:p+nmlen])
      p = p + nmlen
      # version 4
      # self.data.append((dpos, dlen, ulen, flag, typcd, nm[:-1]))
      # version 5
      # nm may have up to 15 bytes of padding
      pos = find(nm, '\0')
      if pos < 0:
          self.data.append((dpos, dlen, ulen, flag, typcd, nm))
      else:
          self.data.append((dpos, dlen, ulen, flag, typcd, nm[:pos]))
      #end version 5


  def tobinary(self):
    """Return self as a binary string."""
    import string
    entrylen = struct.calcsize(self.ENTRYSTRUCT)
    rslt = []
    for (dpos, dlen, ulen, flag, typcd, nm) in self.data:
      nmlen = len(nm) + 1	# add 1 for a '\0'
      # version 4
      # rslt.append(struct.pack(self.ENTRYSTRUCT+`nmlen`+'s',
      #   nmlen+entrylen, dpos, dlen, ulen, flag, typcd, nm+'\0'))
      # version 5
      #   align to 16 byte boundary so xplatform C can read
      toclen = nmlen + entrylen
      if toclen % 16 == 0:
          pad = '\0'
      else:
          padlen = 16 - (toclen % 16)
          pad = '\0'*padlen
          nmlen = nmlen + padlen
      rslt.append(struct.pack(self.ENTRYSTRUCT+`nmlen`+'s',
                      nmlen+entrylen, dpos, dlen, ulen, flag, typcd, nm+pad))
      # end version 5

    return string.join(rslt, '')

  def add(self, dpos, dlen, ulen, flag, typcd, nm):
    """Add an entry to the table of contents.

       DPOS is data position.
       DLEN is data length.
       ULEN is the uncompressed data len.
       FLAG says if the data is compressed.
       TYPCD is the "type" of the entry (used by the C code)
       NM is the entry's name."""
    self.data.append((dpos, dlen, ulen, flag, typcd, nm))

  def get(self, ndx):
    """return the toc entry (tuple) at index NDX"""
    return self.data[ndx]

  def __getitem__(self, ndx):
    return self.data[ndx]

  def find(self, name):
    """Return the index of the toc entry with name NAME.

       Return -1 for failure."""
    for i in range(len(self.data)):
      if self.data[i][-1] == name:
        return i
    return -1

class CArchive(archive.Archive):
  """An Archive subclass that an hold arbitrary data.

     Easily handled from C or from Python."""
  MAGIC = 'MEI\014\013\012\013\016'
  HDRLEN = 0
  TOCTMPLT = CTOC
  TRLSTRUCT = '!8siiii'
  TRLLEN = 24
  LEVEL = 9
  def __init__(self, path=None, start=0, len=0):
    """Constructor.

       PATH is path name of file (create an empty CArchive if path is None).
       START is the seekposition within PATH.
       LEN is the length of the CArchive (if 0, then read till EOF). """
    self.len = len
    archive.Archive.__init__(self, path, start)

  def checkmagic(self):
    """Verify that self is a valid CArchive.

        Magic signature is at end of the archive."""
    #magic is at EOF; if we're embedded, we need to figure where that is
    if self.len:
      self.lib.seek(self.start+self.len, 0)
    else:
      self.lib.seek(0, 2)
    filelen = self.lib.tell()
    if self.len:
      self.lib.seek(self.start+self.len-self.TRLLEN, 0)
    else:
      self.lib.seek(-self.TRLLEN, 2)
    (magic, totallen, tocpos, toclen, pyvers) = struct.unpack(self.TRLSTRUCT,
                        self.lib.read(self.TRLLEN))
    if magic != self.MAGIC:
      raise RuntimeError, "%s is not a valid %s archive file" \
        % (self.path, self.__class__.__name__)
    self.pkgstart = filelen - totallen
    if self.len:
      if totallen != self.len or self.pkgstart != self.start:
        raise RuntimeError, "Problem with embedded archive in %s" % self.path
    self.tocpos, self.toclen = tocpos, toclen

  def loadtoc(self):
    """Load the table of contents into memory."""
    self.toc = self.TOCTMPLT()
    self.lib.seek(self.pkgstart+self.tocpos)
    tocstr = self.lib.read(self.toclen)
    self.toc.frombinary(tocstr)

  def extract(self, name):
    """Get the contents of an entry.

       NAME is an entry name.
       Return the tuple (ispkg, contents).
       For non-Python resoures, ispkg is meaningless (and 0).
       Used by the import mechanism."""
    if type(name) == type(''):
      ndx = self.toc.find(name)
      if ndx == -1:
        return None
    else:
      ndx = name
    (dpos, dlen, ulen, flag, typcd, nm) = self.toc.get(ndx)
    self.lib.seek(self.pkgstart+dpos)
    rslt = self.lib.read(dlen)
    if flag == 1:
      rslt = zlib.decompress(rslt)
    if typcd == 'M':
      return (1, rslt)
    return (0, rslt)

  def contents(self):
    """Return the names of the entries"""
    rslt = []
    for (dpos, dlen, ulen, flag, typcd, nm) in self.toc:
      rslt.append(nm)
    return rslt

  def add(self, entry):
    """Add an ENTRY to the CArchive.

       ENTRY must have:
         entry[0] is name (under which it will be saved).
         entry[1] is fullpathname of the file.
         entry[2] is a flag for it's storage format (0==uncompressed,
         1==compressed)
         entry[3] is the entry's type code.
         Version 5:
           If the type code is 'o':
             entry[0] is the runtime option
             eg: v  (meaning verbose imports)
                 u  (menaing unbuffered)
                 W arg (warning option arg)
                 s  (meaning do site.py processing."""
    (nm, pathnm, flag, typcd) = entry[:4]
    # version 5 - allow type 'o' = runtime option
    try:
      if typcd == 'o':
          s = ''
          flag = 0
      elif typcd == 's':
          # If it's a source code file, add \0 terminator as it will be
          # executed as-is by the bootloader.
          s = open(pathnm, 'r').read()
          s = s + '\n\0'
      else:
          s = open(pathnm, 'rb').read()
    except IOError:
      print "Cannot find ('%s', '%s', %s, '%s')" % (nm, pathnm, flag, typcd)
      raise
    ulen = len(s)
    if flag == 1:
      s = zlib.compress(s, self.LEVEL)
    dlen = len(s)
    where = self.lib.tell()
    if typcd == 'm':
      if find(pathnm, '.__init__.py') > -1:
        typcd = 'M'
    self.toc.add(where, dlen, ulen, flag, typcd, nm)
    self.lib.write(s)

  def save_toc(self, tocpos):
    """Save the table of contents to disk."""
    self.tocpos = tocpos
    tocstr = self.toc.tobinary()
    self.toclen = len(tocstr)
    self.lib.write(tocstr)

  def save_trailer(self, tocpos):
    """Save the trailer to disk.

       CArchives can be opened from the end - the trailer points
       back to the start. """
    totallen = tocpos + self.toclen + self.TRLLEN
    if hasattr(sys, "version_info"):
        pyvers = sys.version_info[0]*10 + sys.version_info[1]
    else:
        toks = split(sys.version, '.', 2)
        pyvers = int(toks[0])*10 + int(toks[1])
    trl = struct.pack(self.TRLSTRUCT, self.MAGIC, totallen,
                      tocpos, self.toclen, pyvers)
    self.lib.write(trl)

  def openEmbedded(self, name):
    """Open a CArchive of name NAME embedded within this CArchive."""
    ndx = self.toc.find(name)
    if ndx == -1:
      raise KeyError, "Member '%s' not found in %s" % (name, self.path)
    (dpos, dlen, ulen, flag, typcd, nm) = self.toc.get(ndx)
    if flag:
      raise ValueError, "Cannot open compressed archive %s in place"
    return CArchive(self.path, self.pkgstart+dpos, dlen)
